Try the rock available to you
After training, interact with a rock the game currently lets you attempt. When it lifts, collect the egg underneath before moving on to another target.
Use a failed attempt as a checkpoint
If your character cannot lift a rock, return to Strength and Speed training or use an available upgrade. The public description does not name a required stat value or a specific lifting control.
Move up as your options change
The game describes upgrading to lift bigger rocks. Recheck the available rocks after a meaningful upgrade rather than following a guessed rock order from another experience.
Rock list and thresholds
No official rock catalogue, weight table, zone sequence, or stat threshold is published in the game description. Treat any such numbers as unverified until confirmed in the current game.